Improvement in mortising-chisel



OTIS ADAMS AND JAMES HATCH, OF SAN FRANCISCO, CALIFORNIA.

Letters Patent No.v82,058, dated September 15, 1868.

IMPROVEMENT IN MORTISING-CHISEL.

@te 'Stimuli referat ic in time Enters ntmt :mh mating pitt nf the same.

TO ALL WHOM IT MAY CONCERN: l

- Beit known that we, OTIS ADAMS and JAMES HATc-B, of the city and county of San Francisco, and State of California, have invented certain Improvements in the Common Mortising-Chisel, applicable particularly t0 the machine-mortising chisel and we do hereby declare that the following is a full, clear, and exact description thereof.

Our invention consists 'in providing the common chisel with two lips, so formed and placed as to clear the mortise of the core or chips while the chisel is in operation.

In order to enable others skilled in the art to make and use our invention, we will proceed to describe the construction and operation of the same with reference to the accompanying drawings, forming a part of this specification, in which similar letters of reference in the different figures indicate the same parts, and in which- Figure 1 is a perspectiveview of edge-end of a chisel having our improvements. 7.,

Figur-e2 is a. back view of the same.

Figure '3 is a front or face view of the same.

Figure 4 is a side view 4of the same.

Figure 5 is a transverse-section view in the line :v x, figs. 2, 3, and 4. i

Figure 6 is a transverse-section view in the line yy, iigs. 2., 3, and 4.-.

. For the' purposes'of description, let the shank-end of the chisel be called its upper end, and the opposite one becalled the lower end, and let the surface on which the bevel is made be called the back, and the opposite one be called the face, and the remaining two surfaces of the cube be called the sides.`

The lowerend'of' the-chisel'is bevelled to an edge, in the ordinary manner, except that a'thick lip is left on each side, as shown by the drawings. Y

The lower end of the lip has a double bevel, to wit, the ordinary chisel-bevel, to an edge, at the lower and front corner, a, (which we callthc longitudinal bevel,) and another bevel to au edge at and along the lower end and outer side, b, of the lip, (which we will call the-lateral bevel.)

` Boththese bevels are muchmore obtuse than the ordinary chisel-bevel, while the bevel of the main blade,

c, betweenthe lips, 'is considerably more acute than the ordinary lipless` mortising-chisel.

Another peculiarity of the lip is, that it is thickest at its lowerback corner, d, andbecomes gradually thinner as it approaches the main blade.

And still another peculiarity is, that the'lip is thicker at its lower end(ata) than at its upper end, (at e,) thus making the space between the lips doubly dove-tailed that is to say, this space enlarges both inwardly (towards the Amain blade).and upwardly. K

v The lips extend somewhat below the main edge, as shown by the drawings.

The operation is as follows The lps chip is cut in advance of the main chip by the edge a. It is then pressed backward abruptly by thelongitudinal bevel, and, at the same time, is twisted inwardly by the-lateral bevel, and thus broken clear of the main chip, and left crumbled and loose in the mortise.

The main chip passes upward through the channel lbetween the lips, being slightly compressed at the lowest and smallestpart of the passage. Y

The d ouble dove-tail prevents the chip from escaping backwardly with the lip-chip, ordownwards, as the chisel is withdrawn from the mortise, leaving it to be forced upwards clear of all obstructions, and thrown out of the mortise, together with the loose Alip-chips, by the upward movement of the chisel.

Theside edges of the lips scrive to smooth the sides of the mortise in a very satisfactory manner.

i We are aware that mortising-chisels have been made with lips at right angles to the main part or body ofthe chisel, and the ends of the lips bcvelled and inclined, and wc thereforetdo not claim a chisel so constructed; but

What we do claim, and desire to secure by Letters Patent, isl 1 Making the lips bevel'led from Vthe edge to the main part of the chisel, and with the ends bevclledv and inclined, as herein set forth.

San Francisco, December 2l, 1867.

Oris ADAMS,

` JAMES HATCH.

Witnesses:

ALFRED Rxx, J. F. Cownsnr. 

